1. Field of the Invention
The present invention relates to photolithographic projection and in particular to an exposure system, an exposure method, and a method for manufacturing a semiconductor device.
2. Description of the Related Art
As the method for projecting an image of a mask pattern on a photomask onto a resist layer, a single shot exposure method and a scanning exposure method are used. By the single shot exposure method, all portion of the mask pattern is irradiated by light to form a latent image of a resist pattern on the resist layer in one shot. On the contrary, by the scanning exposure method, the photomask and a semiconductor substrate coated with the resist layer are scanned simultaneously during the image of the mask pattern is projected onto the resist layer to form the latent image of the resist pattern.
The scanning exposure method provides a constant contrast. Recently, the scanning exposure method has been widely introduced to the process for manufacturing the semiconductor device to keep pace with shrinking chip dimensions. Japanese Patent Laid-Open Publication No. 2001-244172 discloses a method to correct a dimensional error of the resist pattern caused by the scanning exposure method. However, there is no method for forming the resist pattern having the constant line width in the case where the mask pattern has a manufacturing error.